Physconia Labrata, a New Species from Western North America and Asia

Running head: Esslinger et al.: A new Physconia species from western North America and Asia Physconia labrata, a new species from western North America and Asia Theodore L. Esslinger1,4, Bruce McCune2 and Diane L. Haughland3 1 Department of Biological Sciences #2715, Box 6050, North Dakota State University, Fargo, ND 58108-6050, U.S.A.; 2 Department of Botany and Plant Pathology, Cordley 2082, Oregon State University, Corvallis, OR 97331-2902, U.S.A.; 3 Alberta Biodiversity Monitoring Institute, Royal Alberta Museum, 12845 102 Ave., Edmonton, Alberta, T5N 0M6 Canada ABSTRACT. A new species belonging to the lichen genus Physconia is described from Alaska and the Canadian and American Rocky Mountains and adjacent forested regions. It is also reported from China, Nepal, India and Siberia. The new species, Physconia labrata, is superficially similar to P. perisidiosa, but can be distinguished by having a blackened, corticate lower surface and a paraplectenchymatous upper cortex. KEYWORDS. Physciaceae, cortex anatomy, phylogeny, phytogeography, Alberta, Alaska, New Mexico. 4 Corresponding author’s e-mail: [email protected] DOI: 10.1639/0007-2745-120.4.xxx The lichen genus Physconia was segregated from Physcia by Josef Poelt in 1965 (Poelt 1965), and the first North American checklist in which the genus appeared was the last Hale & Culberson version (1970), where only six species were listed. Two of these were Eurasian species which were later determined to not occur in North America (Esslinger 1994). In the most recent online version of the checklist (Esslinger 2016), the number of Physconia species listed has grown to thirteen. Most of the increase is due to the discovery of new or previously described but misunderstood species, some of which are apparently endemic to North America (Esslinger 1994, 2000, 2002). Over many years, during on-going work on the lichen genus Physconia by the first author, occasional specimens of supposed P. perisidiosa (Erichsen) Moberg from North America and Asia were found to have an unusual lower surface, which was corticate to the lobe ends and largely blackened, whereas the lower surface of P. perisidiosa lacks a well-formed lower cortex, especially at the periphery, which is typically pale and fibrous, often with blackened striations. Because of its distinctive reflexed and labriform soralia, which it shares with P. perisidiosa, this new taxon was given the working or herbarium name of P. labrata. Over the past several years, during work on lichens in Alaska and Alberta involving the second and third authors, respectively, more specimens of this distinctive taxon were found and communicated to the first author. Most specimens from Alberta were collected during systematic lichen surveys conducted by a province-wide biodiversity monitoring initiative, the Alberta Biodiversity Monitoring Institute, (www.abmi.ca). METHODS Thin-layer chromatography. Attempts to extract and identify secondary compounds were made using the standardized TLC methods of Culberson & Kristinsson (1970) and Culberson (1972). DNA extraction and PCR amplification. We chose to analyze nuclear internal transcribed spacer (ITS) sequences in keeping with the selection of this locus as the barcoding region for fungi, and its common use by others working on species-level problems in Physconia (Cubero et al. 2004; Divakar et al. 2007; Lohtander et al. 2007, 2008). We attempted to obtain DNA sequences for all six recently collected specimens of P. labrata that were available to us and of adequate size for sampling. Of these, we had success with only two, although we had higher rates of success with other Physconia specimens sequenced for this study (Table 1). Although a sampling of two specimens of a new species is fewer than we prefer, the species was sufficiently well defined morphologically to proceed with its description. Sampling outside the new species focused on geographic and phylogenetic neighbors (Table 1). Extraction and amplification protocols are in McCune & Curtis (2012). Primers for amplifying nuclear ITS were ITS1F (Gardes & Bruns 1993) and ITS4 (White et al. 1990). In addition to the amplification primers, the following primers were used for sequencing: ITS2 and ITS3. Staden 1-6-0 (SourceForge.net) was used to quality check the raw sequence, align the two sequencing runs per PCR product and generate a consensus sequence for phylogenetic analyses. Phylogenetic analyses. We inferred phylogenetic relationships from sequences of rDNA from two specimens of the putative new species, along with seven additional Physconia specimens (Table 1), and 50 Physconia specimens already represented in GenBank. We also included Anaptychia elbursiana (Szatala) Poelt as an outgroup. ITS sequences selected from GenBank represented species across Physconia, with emphasis on taxa with similar morphology, especially P. grumosa and P. perisidiosa. Sequences were aligned with Geneious alignment using default settings (cost matrix: 65%, gap open penalty 12, gap extend penalty 3), then adjusted manually. The ends of the alignments were then trimmed to a nearly equal number of sites for all sequences, including all of ITS1, 5.8S, and ITS2. Alignment gaps were treated as missing data. Phylogenetic trees were obtained by maximum likelihood analysis of the ITS data, using the GTR (general time-reversible) model and Geneious defaults, except we used the “BEST” (slower) topology search and three substitution rate categories, using the PhyML (Guindon et al. 2010) plug-in to Geneious 5.4.3 (Drummond et al. 2011). Statistical support for branches was evaluated with 1000 bootstrap resamplings. Excluding the outgroup, the alignments had 201 variable sites of 503 in the ITS. RESULTS In addition to the distinctive lower surface color and structure, which drew original attention to this new taxon, subsequent anatomical study of longitudinal lobe sections also revealed that the upper cortex is not scleroplectenchymatous as in P. perisidiosa, but rather it is distinctly paraplectenchymatous in mature thallus regions (1.5–2 mm or more from the lobe tips). It appears, therefore, that despite their superficial similarities, this new taxon is not closely related to P. perisidiosa. DNA sequencing was successful for two specimens, including the holotype from Alberta and one specimen from Alaska, and this also confirmed the distinct nature of this taxon. In fact, in the phylogenetic tree including these sequences (Fig. 1), the new taxon appears closest to P. grumosa Kashiw. & Poelt. Interestingly, this closest genetic relative P. grumosa does not share the paraplectenchymatous upper cortex of P. labrata, but instead has a distinctly scleroplectenchymatous upper cortex. Although all available evidence from previous work has shown that upper cortex type is a good species level character in Physconia (e.g., Divakar et al. 2007; Esslinger 1994; Poelt 1966), examination of our tree (Fig. 1) or any of those published previously (Cubero et al. 2004; Divakar et al. 2007; Lohtander et al. 2007, 2008), shows that species with the two types of upper cortex are distributed rather randomly in the tree, and do not clearly identify any large species groupings or possible subgenera. Based on these morphological and anatomical comparisons as well as phylogenetic analyses of ITS sequences from two specimens, here we describe a new species, Physconia labrata Essl., McCune & Haughland. Phylogenetic reconstruction. Physconia labrata was readily distinguished from other Physconia species by ITS sequences. Phylogenetic reconstruction showed the P. labrata specimens to form a supported monophyletic group with 90% bootstrap support (Fig. 1). Furthermore, P. labrata shows reciprocal monophyly and a supported sister relationship with P. grumosa. Both P. labrata and P. grumosa were placed in a supported clade (91% bootstrap support), which in turn fell in an unsupported clade with P. kurokawae Kashiw., P. leucoleiptes (Tuck.) Essl., and two clades of P. muscigena (Ach.) Poelt. TAXONOMY Physconia labrata Essl., McCune & Haughland, sp. nov. Figs. 2, 3, 4A & 5A MYCOBANK MB 822644 A sorediate species, bearing soredia on lobe ends and edges, the soralia becoming more or less labriform; differing from the superficially similar species Physconia perisidiosa by having a darkened, corticate lower surface and a paraplectenchymatous upper cortex. TYPE: CANADA. ALBERTA: ca. 30 km N of Hinton, AB, on Hwy. 40 in William Switzer Provincial Park, east on Cache Lake & Graveyard Lake gravel access road, at parking lot for wildlife viewing blind, ca. 53.5026°N, 117.82146°W, 1203 m. elev., on trunk of Picea glauca, 7 Nov 2015, (holotype: Diane L. Haughland, #2015-1a, PMAE; isotypes: #2015-1b, CAN, #2015-1c, herb. Esslinger). Description. Thallus foliose, irregular to distinctly orbicular, mostly appressed, up to ca. 4 cm in diameter but usually smaller, occasionally composed of numerous small, disconnected lobes, which tend to be ascendant and sorediate. Lobes linear to more often shorter, irregular-rounded or flabellate and partly imbricate, (0.7–) 1–2 mm broad, mostly flat to weakly concave or convex, rarely with a few small, scattered lobules. Upper surface gray to gray-brown or commonly brown to dark reddish brown, with a partial (lobe ends) or sometimes almost complete pruina. Sorediate, the soralia on and under lobe ends or edges, which become ascendant or somewhat reflexed and weakly to more strongly labriform; soredia usually granular, darkening with age, sometimes becoming somewhat isidioid in older

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